Exclusive 'Sister Wives' sneak peek: One wife isn't happy anymore

It looks like Kody Brown’s run of wedded bliss — times four — has finally hit a snag.

In an exclusive sneak peek TLC provided TODAY.com, it becomes evident that Kody and Christine, aka bride number three, are in the midst of a major relationship shakeup.

“You know, I think Kody and Christine have both been very open with us that they’re at a point that what was working needs to be changed,” Janelle, Kody’s second wife, explained. “It’s different now, and they are working on their relationship. I feel the tension. It shakes up the foundation of the family when one of the couples is struggling.”

And according to Christine, it’s one heck of a struggle.

“I don’t know if I care if it’s perfect anymore, or if it’s what he wants anymore,” she said. “It’s like it’s just so much work. I know there’s a big pay-off. I know for years and years we had a great marriage and a great thing, and I just don’t know what I want anymore.”

What does Kody have to say about the his marital woes? Find out when “Sister Wives” airs Sunday at 9 p.m. ET.